From the Guidelines
Vitamin B12 repletion in patients with Crohn's disease should be done through intramuscular injection of 1000 mg of vitamin B12 every other day for a week, followed by monthly injections for life, as recommended by the most recent guidelines 1. This approach is necessary due to impaired intestinal absorption in Crohn's disease patients, particularly those with ileal involvement or resection. The ileum is the primary site of vitamin B12 absorption, and its inflammation or resection can lead to deficiency.
- Key factors to consider in vitamin B12 repletion include:
- Extent of ileal resection: patients with more than 20 cm of ileum resected should receive prophylactic vitamin B12 injections every month indefinitely 1.
- Presence of clinical deficiency features: patients with clinical deficiency should be treated with intramuscular vitamin B12 injections every other day for a week, followed by monthly injections for life 1.
- Yearly screening for vitamin B12 deficiency is recommended for patients with ileal involvement and/or resection and/or clinical deficiency features 1. While oral therapy may be effective, parenteral supplementation remains the reference standard, although oral supplementation may become more widely accepted in the future 1. Regular monitoring of vitamin B12 levels every 3-6 months is essential to ensure adequate repletion and prevent clinical manifestations of deficiency.
From the Research
Repleting Vitamin B12 in Crohn's Patients
To replete vitamin B12 in patients with Crohn's disease, several approaches can be considered based on the available evidence:
- Oral cyanocobalamin has been shown to be effective in treating vitamin B12 deficiency in Crohn's disease patients, with a dose of 1 mg/day being commonly used 2.
- The oral route has been demonstrated to be effective for both acute treatment and long-term maintenance of vitamin B12 levels in patients with Crohn's disease, with an effectiveness rate of 81.7% after a mean follow-up of 3 years 2.
- It is essential to identify and address the underlying causes of vitamin B12 deficiency, such as terminal ileal resection or inflammation, as these can impact the effectiveness of treatment 3.
- Regular monitoring of vitamin B12 and folate levels is crucial in patients with Crohn's disease, as deficiencies in these vitamins can lead to complications such as thrombosis and its associated risks 4.
Treatment Options
The choice of treatment for vitamin B12 deficiency in Crohn's disease patients may involve:
- Methylcobalamin (MeCbl) and adenosylcobalamin (AdCbl) are the two active co-enzyme forms of vitamin B12, and treatment may involve a combination of these or hydroxocobalamin 5.
- The oral route has been proven to be comparable to the intramuscular route for rectifying vitamin B12 deficiency, offering a more convenient and less invasive option for patients 5.
Prevalence and Risk Factors
Vitamin B12 deficiency is common in patients with Crohn's disease, with a prevalence of 33% compared to 16% in ulcerative colitis 3.
- Risk factors for vitamin B12 deficiency in Crohn's disease include terminal ileal resection length, ileal inflammation, and disease characteristics on magnetic resonance imaging 3.
- Patients with Crohn's disease are at a higher risk of developing vitamin B12 insufficiency and hyperhomocysteinemia, which can have clinical implications 6.